First off, I didn't know if I should put this in off-topic or people portrait so MODS feel free to move it.

I was thinking for doing some wedding photography when I get older... I was wondering if my idea is a good one...

This is my idea- Tag along with another photographer (who happens to be related to me) and be a second photographer without being payed. This would give me the knowledge and confidence that I don't have at this time. I want to be able to go into my first one stress free and I think that this may give me that extra edge. The reason it may not be a good idea in my eyes is I want money... That is the ultimate goal of this whole thing...

'Tag Along' with another photographer are very common here in Brunei especially wedding & some Formal family function. The main reason of it is not only covered the relative's event they want to learn & share experience with other Photographer. So your idea should be fine anyway